There is known an electronic system with conventional redundancy, comprising two processing chains arranged in parallel. The first chain includes a first processing unit able to implement algorithms, and a plurality of first input/output boards connected in series with the first unit. Each first board is capable of acquiring input signals delivered by a plurality of sensors, and/or of generating output signals to control a plurality of actuators. The second chain includes a second processing unit able to implement the same algorithms as those implemented by the first unit, and a plurality of second boards connected in series with the second unit. Each second board is able to acquire the same input signals as a respective first board, and able to generate the same output signals as said respective first board. In other words, the second processing unit is functionally identical to the first processing unit, and each second board is functionally identical to a respective first board. The first processing unit and the second processing unit are interconnected by a first and a second wired communication link, the second link being redundant with respect to the first link.
However, the failure of a processing unit makes the corresponding chain totally inoperative. The failure of a board makes the corresponding chain inoperative from this failing board, for the other boards arranged downstream with respect to the processing unit arranged upstream. Such a failure of a component therefore significantly reduces the reliability of the set of two chains. Furthermore, there is a significant common mode between the two processing units, which also reduces the reliability of the set of two chains.